Spam is unsolicited, typically commercial electronic mail (xe2x80x9ce-mailxe2x80x9d). It clutters e-mail boxes, undesirably occupies space in computer memory (e.g., on a hard disk), and is generally a nuisance.
A known general approach to handling spam is called filtering. Filtering includes techniques designed to distinguish a spam message from a message that is not spam, and to dispose of a message identified as spam in a particular fashion (e.g., automatically deleting it, flagging it, etc.)
A known technique for filtering spam from other types of e-mail is performed at least partly in a manual fashion by a spam recipient and a system administrator. Upon receiving and identifying a message as spam (e.g., by reading it), the recipient forwards a copy of the message to the system administrator, indicating to the administrator that the message is spam. The administrator reads at least part of the spam message (e.g., the header, the body, etc.) and identifies at least one string (a xe2x80x9cspam stringxe2x80x9d) in the header and/or body that is likely to be reproduced in other spam messages. The header of an e-mail includes addressing and subject information. The body includes the text of the message. Examples of a spam string include the address of the sender (e.g., xe2x80x9cgrthibault@specmorl.comxe2x80x9d), a Uniform Resource Locator (e.g., xe2x80x9chttp://www.sellmore.comxe2x80x9d), or a text string xe2x80x9cmake $$$ wile working at home!xe2x80x9d
The system administrator places a spam string in a file or database. Subsequent incoming e-mail messages are searched for the occurrence of a spam string that is included in the administrator""s spam string database. If such a string is found in an incoming e-mail message, the message is blocked, and is not delivered to its intended recipient.
Although this known filtering system and method can identify and block spam, it is disadvantageously time consuming on the part of both the user-recipient of the spam, who has to read at least part of the spam, and then forward it to the administrator. This known system is also disadvantageously time-consuming for the system administrator, who also has to read at least part of the spam, identify a spam string, and then enter it in a spam string database. Further, this known system can be circumvented by the spam sender by varying the source address and text strings inside its spam.